1. Field of the Invention
The present invention relates to a combustion apparatus wherein a fuel injection portion is located rearward of a gas passable solid (upstream of the solid as viewed in an air flow direction), and a thermal facility provided with the combustion apparatus.
2. Description of Related Art
In a conventional burner, a fuel injection portion is located so as to face a combustion chamber. As a result, combustion is conducted near the fuel injection portion of the burner, so that a temperature of the fuel injection portion is high. Particularly, in a regenerative combustion type burner, since the fuel injection portion is located frontward of a heat storage member (on a combustion chamber side), the fuel injection portion is at a very high temperature.
Further, as a special case, Japanese Utility Model Publication SHO 62-118925 discloses a radiant tube wherein a fuel injection nozzle is located rearward of a heat storage member such that a tip of the nozzle contacts the heat storage member.
However, the above-described conventional apparatuses have the following problems:
With the burner where the fuel injection portion faces the combustion chamber, since the fuel injection portion is at a high temperature, the life of the burner is shortened. If the fuel injection portion is made from heat proof material, cost will be increased and machining will be difficult. Further, since a complicated mechanism cannot be provided to a high temperature portion, the burner structure will have various limitations.
With the burner in which the fuel injection portion is located rearward of the heat storage member like Japanese Utility Model Publication SHO 62-118925, according to tests conducted, it was seen that no flame was formed due to insufficient mixture of fuel and air. If the fuel injection portion was spaced apart from the heat storage member in order to pre-mix fuel and air, when exhaust gas flows through the heat storage member to heat the heat storage member to a high temperature, the mixture of fuel and air self-ignited and burned within the heat storage member to melt the heat storage member. Therefore, the burner having the fuel injection portion rearward of the heat storage member could not be actually used.